Under the combined constraints of rapid rotation, sphericity, and magnetic field, motions in planetary cores get organized in a peculiar way. Classical hydrodynamic turbulence is not present, but turbulent motions can take place under the action of the buoyancy and Lorentz forces. Laboratory experiments, such as the rotating spherical magnetic Couette DTS experiment in Grenoble, help us understand what motions take place in planetary core conditions.
Sous les contraintes combinées de la rotation rapide, de la sphéricité et du champ magnétique, les écoulements dans les noyaux planétaires s'organisent d'une manière particulière. La turbulence hydrodynamique classique n'est pas présente mais des mouvements turbulents peuvent se mettre en place sous l'action des forces d'Archimède et de Lorentz. Des expériences de laboratoire comme l'expérience DTS de Couette sphérique sous champ magnétique à Grenoble, nous aident à comprendre les écoulements qui peuvent exister dans les conditions des noyaux planétaires.
Mot clés : Dynamo, Noyau planétaire, DTS, Couette sphérique
Henri-Claude Nataf 1; Nadège Gagnière 1
@article{CRPHYS_2008__9_7_702_0, author = {Henri-Claude Nataf and Nad\`ege Gagni\`ere}, title = {On the peculiar nature of turbulence in planetary dynamos}, journal = {Comptes Rendus. Physique}, pages = {702--710}, publisher = {Elsevier}, volume = {9}, number = {7}, year = {2008}, doi = {10.1016/j.crhy.2008.07.009}, language = {en}, }
Henri-Claude Nataf; Nadège Gagnière. On the peculiar nature of turbulence in planetary dynamos. Comptes Rendus. Physique, Volume 9 (2008) no. 7, pp. 702-710. doi : 10.1016/j.crhy.2008.07.009. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2008.07.009/
[1] Generation of magnetic field by a turbulent flow of liquid sodium, Phys. Rev. Lett., Volume 98 (2006), p. 044502
[2] Magnetic field reversals in an experimental turbulent dynamo, Eur. Phys. Lett., Volume 77 (2007), p. 59001
[3] Magnetic Field Saturation in the Riga dynamo experiment, Phys. Rev. Lett., Volume 86 (2001), pp. 3024-3027
[4] Experimental demonstration of a homogeneous two-scale dynamo, Phys. Fluids, Volume 13 (2001), pp. 561-564
[5] The magneto-hydrodynamics of a rotating fluid and the Earth's dynamo problem, Proc. R. Soc. Lond. A, Volume 274 (1963), pp. 274-283
[6] Experimental study of super-rotation in a magnetostrophic spherical Couette, Geophys. Astrophys. Fluid Dyn., Volume 100 (2006), pp. 281-298
[7] Rotating spherical Couette flow in a dipolar magnetic field: Experimental study of magneto-inertial waves, J. Fluid Mech., Volume 604 (2008), pp. 175-197
[8] H.-C. Nataf, T. Alboussière, D. Brito, P. Cardin, N. Gagnière, D. Jault, D. Schmitt, Rapidly rotating spherical Couette flow in a dipolar magnetic field: An experimental study of the mean axisymmetric flow, Phys. Earth Planet. Inter. (2008), doi: | DOI
[9] Towards a rapidly rotating liquid sodium dynamo experiment, Magnetohydrodynamics, Volume 38 (2002), pp. 177-189
[10] Axial invariance of rapidly varying diffusionless motions in the Earth's core interior, Phys. Earth Planet. Inter., Volume 166 (2008), pp. 67-76
[11] Axisymmetric flow between differentially rotating spheres in a dipolemagnetic field, J. Fluid Mech., Volume 344 (1997), pp. 213-244
[12] Inertial waves driven by differential rotation in a planetary geometry, Geophys. Astrophys. Fluid Dyn., Volume 101 (2007), pp. 469-487
[13] Quasi-geostrophic flows responsible for the secular variation of the Earth's magnetic field, Geophys. J. Int., Volume 173 (2008), pp. 421-443
[14] Boundary layer instability at the top of the Earth's outer core, J. Comput. Appl. Math., Volume 166 (2004), pp. 123-131
[15] Dissipation at the core-mantle boundary on a small-scale topography, J. Geophys. Res., Volume 111 (2006), p. B04413
[16] Magnetic and viscous coupling at the core-mantle boundary: inferences from observations of the Earth's nutations, Geophys. J. Int., Volume 171 (2007), pp. 145-152
[17] Modeling nutation and precession: very long baseline interferometry results, J. Geophys. Res. 107 (2002) (B4, 2069)
[18] Quasi-geostrophic kinematic dynamos at low magnetic Prandtl numbers, Earth Planet. Sci. Lett., Volume 245 (2006), pp. 595-604
[19] Commutation error correction for large eddy simulations of convection driven dynamos, Geophys. Astrophys. Fluid Dyn., Volume 101 (2007), pp. 429-449
[20] Torsional magnetohydrodynamic vibrations in the Earth's core and variations in day length, Geomag. Aeron., Volume 10 (1970), pp. 1-8
[21] Torsional oscillations and the magnetic field within the Earth's core, Nature, Volume 388 (1997), pp. 760-763
[22] Torque balance, Taylor's constraint and torsional oscillations in a numerical model of the geodynamo, Phys. Earth Planet. Int., Volume 140 (2003), pp. 29-51
[23] Westward drift, core motions and exchanges of angular momentum between core and mantle, Nature, Volume 333 (1988), pp. 353-356
[24] Investigation of a secular variation impulse using satellite data: the 2003 geomagnetic jerk, Earth Planet. Sci. Lett., Volume 255 (2007), pp. 94-105
[25] Geomagnetic dynamo: an improved laboratory model, Nature, Volume 219 (1968), pp. 717-718
Cited by Sources:
Comments - Policy